The invention relates to a contactor in which the body is constituted by a common base connected to two parallel shaped metallic walls each having on its internal surface a rib serving to guide and support the fixed elements of a removable electro-magnet which is provided with members adapted to cooperate with the said ribs, and which attracts a movable armature. Such a contactor which is particularly adapted to the control of polyphase circuits in which high currents circulate is known from French Pat. No. 2284971.
When the fixed elements of the electro-magnet have a certain dissymetry with respect to the body, for example when the winding comprises an auxiliary contact or lateral coupling terminals, it is necessary to avoid that its positioning is carried out in an incorrect manner; furthermore, it is recommended to arrange things such that the heaviest of the fixed elements, in this case the core of the electro-magnet, remain engaged with the body in the position where the winding can already be separated; finally, it is important to establish for each of the elements methods of engagement on the body which shall be distinct, according to whether these latter will be submitted, or not, to blows.